High accuracy low leakage valve for high pressure applications

Abstract

A high pressure valve assembly (10) comprising a valve sleeve (14) and a valve body (16) slidably mounted in the valve sleeve (14) is disclosed, the valve body (16) and valve sleeve (14) each having first ends (18, 56) and second ends (20, 58). A sidewall (22) extends between the valve sleeve first end (18) and second end (20) which sidewall (22) has an inner surface (24) and an outer surface (26) and at least one opening (30) therethrough. The sidewall (22) also includes at least one channel (40) having a first end (42) facing the inner surface (24) at a first location closer to the first valve sleeve end (18) than to the second valve sleeve end (20) and a second end (44) facing the inner surface (24) at a second location closer to the second valve sleeve end (20) than to the first valve sleeve end (18). A method of using the valve assembly (10) is also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims the benefit of U.S. Provisional Patent Application No. 60 / 492,301, filed Aug. 5, 2003, the entire contents of which is hereby incorporated by reference.[0002]This invention was made with Government support under Contract No. N00019-02-C-3003 awarded by the United States Navy. The Government has certain rights in this invention.FIELD OF THE INVENTION[0003]This invention relates to a valve for high pressure applications, and, more specifically, to a valve for a high pressure fluid metering system that reduces matched clearance leakage between a valve body and a valve sleeve.BACKGROUND OF THE INVENTION[0004]Fluid metering systems requiring high accuracy flow, such as fuel metering systems for gas turbine engines, often use a servo-controlled throttling valve to maintain a constant pressure delta (head pressure) across a metering orifice. In such systems, a supply of burn fuel is directed against a first side of...

AI Technical Summary

Benefits of technology

The present invention provides a valve assembly for a fluid metering system and a gas turbine engine throttle valve assembly that can effectively reduce servo side matched clearance leakage to near zero. The valve assembly includes a valve sleeve with a channel to port metered flow pressure to an annulus. The valve has a single diameter, making it easier to achieve low leakage or drip-tight shutoff. The gas turbine engine throttle valve assembly includes a valve body slidably mounted in the valve sleeve and a control fluid directed against the valve body to shift it between a first position blocking the at least one opening and a second position exposing at least a portion of the opening to the supply fuel. The invention also provides methods for controlling fuel flow and throttle valve outlet flow.

Problems solved by technology

In high pressure systems, the fluid conveying the control pressure against the valve body may leak between the valve body and the valve sleeve and into the valve outlet.

Because this leakage is somewhat unpredictable it varies with temperature and operating conditions, for example, it is often a large contributor to metering system inaccuracy.

System requirements typically call for drip-tight shutoff leakage on throttle valves.

Not only is the dual-diameter matched valve assembly expensive to manufacture, but it is extremely difficult to achieve the low leakage or drip-tight shutoff sealing required in some applications with this valve.

In the dual-diameter configuration, it is also extremely difficult to install a durable drip-tight seal in the upper seal diameter, because the seal 226 must be stretched when it is installed and re-sized after installation.

Seal 226 is exposed to the burn fuel, and these impurities may tend to collect around seal 226, thus degrading performance of the seal and interfering with a drip-tight shutoff.

Images